What is grease?
Grease Grease is a semisolid liquid that consists of a liquid lubricant mixed with a thickener. The oil does the lubricating while the thickener holds the oil and provides a resistance to flow. Soaps (a […]
Tribology Wiki
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Density of Oil
What is oil density? Oil density is a crucial property not only in lubricants but in all fluids. For instance, as the density of a lubricant increases, the fluid becomes thicker. This leads to an […]
Starvation
It is said that a contact operates under “starvation conditions” when an increase of oil supply at the contact would result in an increase of the film thickness at the contact. In other words, when […]
Viscosity Index
What is viscosity index? The viscosity index (VI) is an arbitrary, unitless measure of a fluid’s viscosity change relative to a temperature change. We can say that the it is the dimensionless number that shows how the […]
Flame Hardening
What is flame hardening? By putting the solid red-hot steel into water ( producing martensite), and tempering the quench-hardened steel at a moderate temperature, have been known and used for thousands of years. The extensively […]
Spalling Damage
Bearing Failure Modes Bearing damage, and ultimately, failure, can be caused by a variety of conditions, including improper mounting, poor lubrication, and overloading, to name a few. The mode of damage — what actually happened […]
Types of Lubricant Additives
What Are Lubricant Additives? The additive content in lubricating oils ranges from just a few parts per million to several percentage points. Depending on the function that the additives develop they may be classed as: […]
What is Lubrication?
Lubrication can be defined as the application of some materials between two objects moving relative to each other to allow smooth operation as much as necessary. Either oil or grease is used for rolling bearings […]
Lapping
What is lapping? Lapping is a type of finishing process which is carried out with the help of loose abrasives. In this finishing process, surface smoothening is achieved by the abrasive grains which are supported […]
Friction Coefficient Tables in Air and Vacuum
Friction coefficient tables for solid lubricants, metals, plastics and anti-friction materials Friction coefficient tables for various material pairs in atmosphere and vacuum are provided below. The data was collected from various sources [1,2,3]. See the […]